CVE-2026-80555 (GCVE-0-2026-80555)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:37 – Updated: 2026-08-27 12:40
VLAI
Title
s390/vfio_ccw: Free all memory if cp_init() fails
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Free all memory if cp_init() fails The routine cp_free() is called to unpin/free any memory once an I/O is completed successfully, or if cp_prefetch() fails. But if cp_init() fails, and cp->initialized is not enabled, the same routine cannot be used to free all the memory. An attempt to address this exists in ccwchain_handle_ccw(), where a single call to ccwchain_free() is made for the currently-processed CCW segment. But this will leak other segments (created as a result of a Transfer in Channel) that had been allocated as part of the same channel program. Address this by performing the cleanup outside of the recursive ccwchain_handle_ccw()/ccwchain_loop_tic() logic.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 276bd7ed34d56c48c65c43c0b08f2ee77029b2fa (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < f9bcff265556796834122f95de16d52a8375206c (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 17e01e342af74de12899c206dcc9ec90684703aa (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 152fcb74a26804b70909381c6acc90595a0ae1c1 (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 6a917199aaf97904f5619afe3dfdacb155b03e8c (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 32e3d364a7b8295120d37e6a6bd433d2de26f748 (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 4699b54fada156534cbb39834d47fc9374d7a1f5 (git)
Affected: 8b515be512a2435bb8aedc6390cbe140167f9eb9 , < 74186c2968f8f756ac3226b545b598457c910c75 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.3
Unaffected: 0 , < 5.3 (semver)
Unaffected: 5.10.267 , ≤ 5.10.* (semver)
Unaffected: 5.15.218 , ≤ 5.15.* (semver)
Unaffected: 6.1.185 , ≤ 6.1.* (semver)
Unaffected: 6.6.154 , ≤ 6.6.* (semver)
Unaffected: 6.12.105 , ≤ 6.12.* (semver)
Unaffected: 6.18.46 , ≤ 6.18.* (semver)
Unaffected: 7.1.10 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio_ccw: Free all memory if cp_init() fails\n\nThe routine cp_free() is called to unpin/free any memory once an I/O\nis completed successfully, or if cp_prefetch() fails. But if cp_init()\nfails, and cp-\u003einitialized is not enabled, the same routine cannot be\nused to free all the memory.\n\nAn attempt to address this exists in ccwchain_handle_ccw(), where a\nsingle call to ccwchain_free() is made for the currently-processed\nCCW segment. But this will leak other segments (created as a result\nof a Transfer in Channel) that had been allocated as part of the same\nchannel program.\n\nAddress this by performing the cleanup outside of the recursive\nccwchain_handle_ccw()/ccwchain_loop_tic() logic."
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              "value": "AV:L - The bug is reached when userspace writes the vfio-ccw io_region (VFIO device mmap/write), triggering fsm_io_request() -\u003e cp_init(); on s390 KVM this is driven by QEMU forwarding guest channel-I/O channel programs, requiring local VFIO/device interaction rather than any network protocol.\nAC:L - An attacker can deterministically fail cp_init() after allocating multiple TIC-linked ccwchain segments by crafting a channel program whose early TIC targets succeed and a later one fails (invalid CPA, chain-length/count limit, or dma_rw error), leaking prior segments on every attempt without races.\nPR:N - On s390 KVM with CCW passthrough, a malicious guest can submit crafted multi-TIC channel programs through normal guest I/O; QEMU forwards them to vfio-ccw without the attacker holding host CAP_SYS_ADMIN, root, or other real init-namespace privileges beyond the assigned device.\nUI:N - No victim interaction is required beyond the attacker (or their guest) issuing channel-I/O start requests with a malicious channel program; exploitation does not depend on another user mounting media, accepting prompts, or performing administrative actions at trigger time.\nS:C - The leaked ccwchain, CCW, and page_array allocations are host kernel slab memory; a guest VM triggering this through passthrough crosses the guest-host virtualization boundary by consuming host resources the guest security domain should not affect.\nC:N - This is a kernel memory leak on the cp_init() error path, not a use-after-free, out-of-bounds read, or other memory corruption; leaked objects are orphaned in kernel heap and are not returned to userspace or the guest, so no information disclosure occurs.\nI:N - The flaw only fails to free kernel allocations when cp_init() errors; it does not corrupt memory, modify guest or host data, or provide write or control-flow primitives, and cp-\u003einitialized stays false so cp_free() never runs on the error or close paths.\nA:H - Each failed cp_init() permanently orphans up to CCWCHAIN_COUNT_MAX ccwchain segments (large GFP_DMA allocations), and subsequent cp_init() calls INIT_LIST_HEAD without freeing prior leaks; repeated guest or VFIO I/O requests can exhaust host memory and cause system-wide OOM or severe denial of service."
            }
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "datePublished": "2026-08-26T14:37:22.969Z",
    "dateReserved": "2026-08-26T14:34:25.766Z",
    "dateUpdated": "2026-08-27T12:40:15.211Z",
    "state": "PUBLISHED"
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But this will leak other segments (created as a result\\nof a Transfer in Channel) that had been allocated as part of the same\\nchannel program.\\n\\nAddress this by performing the cleanup outside of the recursive\\nccwchain_handle_ccw()/ccwchain_loop_tic() logic.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/s390/cio/vfio_ccw_cp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"276bd7ed34d56c48c65c43c0b08f2ee77029b2fa\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"f9bcff265556796834122f95de16d52a8375206c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"17e01e342af74de12899c206dcc9ec90684703aa\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"152fcb74a26804b70909381c6acc90595a0ae1c1\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"6a917199aaf97904f5619afe3dfdacb155b03e8c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"32e3d364a7b8295120d37e6a6bd433d2de26f748\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"4699b54fada156534cbb39834d47fc9374d7a1f5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8b515be512a2435bb8aedc6390cbe140167f9eb9\",\"lessThan\":\"74186c2968f8f756ac3226b545b598457c910c75\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/s390/cio/vfio_ccw_cp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.3\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.3\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.267\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.218\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.185\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.154\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.105\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.46\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.10\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.5,\"impactScore\":4.0}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/152fcb74a26804b70909381c6acc90595a0ae1c1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/17e01e342af74de12899c206dcc9ec90684703aa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/276bd7ed34d56c48c65c43c0b08f2ee77029b2fa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/32e3d364a7b8295120d37e6a6bd433d2de26f748\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4699b54fada156534cbb39834d47fc9374d7a1f5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6a917199aaf97904f5619afe3dfdacb155b03e8c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/74186c2968f8f756ac3226b545b598457c910c75\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f9bcff265556796834122f95de16d52a8375206c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.